The present invention relates to athletic shoes and more particularly to cleated athletic shoes.
Cleated or spiked athletic shoes have been designed using a variety of different cleat arrangements to facilitate anchoring the shoe to a playing surface when running or changing directions. The traditional design of such shoes includes a plurality of cleats located on the sole of the shoe, with a main traction cleat located under the large metatarsal joint of the big toe. Downwardly directed force generated during activity by the wearer tends to cause the main traction cleat to impact the ground directly under the metatarsal joint, which acts like a hammer driving the main traction cleat into the ground. An outside cleat is typically placed laterally and slightly rearwardly of the main traction cleat, substantially along the metatarsal joint chain of bones in the foot, which also results in the outside cleat being driven into the ground by the metatarsal joint bones. A major disadvantage with such a design is that using the metatarsal joint to drive cleats into the ground may cause discomfort and bone bruising injuries.
There have been many attempts to improve upon the traditional design of cleated athletic shoes to over-come this problem. George, U.S. Pat. No. 4,347,674 discloses a cleat arrangement with at least three thin arcuate cleats arranged in a ring at the ball portion of the sole. Tanel, U.S. Pat. No. 4,577,422 discloses a circular cleat formed on a forward portion of the sole substantially encompassing the ball of the foot and toe portions of the sole, and is centered at the juncture thereof. Ihlenburg, U.S. Pat. No. 4,914,838 discloses a cleated athletic shoe that relies upon a substantially circular pattern of cleats to specifically address the issue of comfort for the wearer.
With the traditional cleat arrangement where the outside cleat is placed laterally, substantially along the metatarsal joint chain of bones in the foot; and also in the George patent where the rearmost outside cleat is located just rearward of the metatarsal joint chain and the Tanel or Ihlenburg patents with their circular cleat arrangement, the outside cleat, or portion of Tanel's cleat, causes significant destabilization of the player's upright stance when lateral forces are applied to the foot by a significant lateral shift of the wearer's body weight over the outside cleat. In these prior art shoes the outermost or rearward outermost cleat is either directly or significantly in line with this lateral motion, thereby not permitting sufficient room for absorption of the stopping action of the cleat by the leg. This abrupt termination of the motion of the shoe by the outermost cleat being directly in line with or more or less in line with the lateral motion, is much like tripping over an unexpected object.
While circular cleat patterns provide improved comfort over the traditional cleat pattern, by placing the cleats in a substantially circular pattern, where the cleats are placed an equal distance on substantially the same radius from a specific point generally located at the juncture of the center of the phalanges where it intersects the metatarsals or at the ball portion of the shoe, stability and traction is no better than with the traditional cleat pattern. This is because this cleat arrangement is based upon the theory that an athlete who is involved in an activity requiring significant pivot changes of direction does so on the forwardmost portions of his or her feet (e.g., with weight placed on the area forward of the metatarsals toward the end of the toes or phalanges) with the toes flexed and the foot extending forward at a significant angle from the flexed point. This is not the case. In fact, such changes normally occur with the weight placed further back on the sole. Thus, a circular cleat arrangement also in effect causes a person to trip over either the forward medial or rearward lateral cleat when suddenly changing direction while running.
In addition, the foot of the majority of individuals impacts the playing surface in a pronated position, e.g., with the foot turned slightly under thereby impacting the lateral side of the foot before the flat bottom plane of the foot. With cleats on the lateral side of the sole orientated at a right angle to the sole, the cleats impact the ground at an exaggerated angle of attack causing significant torque to be applied to the cleats and the athlete's leg.
Additionally, traditional theory relies primarily upon the direct impact of the weight of the body to drive the cleats into the ground, regardless of the condition of the ground which can, under unfavorable conditions, cause the cleats to recoil off the ground. Finally, the prior art shoes provide a spike of a height similar or equal to the height of the weight bearing cleats at the forwardmost portion of the sole to increase traction. However, such a spike does not have a significant effect on traction and is a major cause of injuries.
What is desired, therefore, is a cleat arrangement that provides for maximum stability and traction, while reducing the likelihood of injury to the foot and leg. The cleat arrangement should also minimize the torque on the leg and not primarily rely upon the weight of the body to drive the cleats into the ground.